Coating apparatus



' R. L. GRIFFIN 1,966,093

July 10, 1934.

COATING APPARATUS Filed Dec. 12, 1928 4 Sheets-Sheet l Iwemar Z &-

July 10, 1934. R. L. GRlFFlN COATING APPARATUS Filed Dec. 12, 1928 -4 Sheets-Sheet 2 y 10, 1934- R. L. GRIFFIN COATING APPARATUS Filed Dec. 12, 1928 4 Sheets-Sheet 3 a N\\ n: 4. N b% y 1934- R. L. GRIFFHQ 1,966,093

COATI'NG APPARATUS I Filed Dec. 12, 1928 mats-Shea -4 Patented July 10, 1934 UNITED STATES COATING APPARATUS Roger L. Griffin, Peabody, Mass, assignor to A. 0. Lawrence Leather Company, Boston, Mass., a

corporation of Maine Application December 12, 1928, Serial No. 325,577

25 Claims.

The present invention relates to coating apparatus and more particularly to apparatus and method of operating the same for applying a coating of viscous material to a sheet of leather or similar material.

One object of the present invention is to provide a coating apparatus and method of operation whereby a smooth continuous coating may be applied with a minimum expenditure of time and labor.

Another object of the invention is to provide an apparatus by which the application of the coating may be readily controlled.

A still further object of the invention is to provide an automatic control whereby articles of irregular shape may be coated without undue loss of material.

With these objects in view, the present invention consists in the coating apparatus hereinafter described and particularly defined in the claims.

In the accompanying drawings, Fig. 1 is a front elevation of so much of the preferred form of the coating apparatus as is necessary to an understanding of the present invention; Fig. 2 is an end elevation of the apparatus as viewed from the right hand end of Fig. 1; Fig. 3 is a top plan view of the apparatus showing the arrangement of the gearing but with some of the parts omitted for clearness; Fig. 4 is a detail view of the pressure equalizing chamber; Fig. 5 is a detail view of the sprayer assembly with the automatic spray control; Fig. 6 is a diagrammatic plan view showing the operation of the automatic control; Fig. 7 is a wiring diagram of the automatic control; Fig. 8 is a plan view of a modified form of control; and Fig. 9 is a diagrammatic front view of the control shown in Fig. 8.

As herein illustrated and described, the present invention is embodied in an apparatus for applying coating material to leather or other hides for the manufacture of patent leather. Referring to Fig. 1, the hide 10 is secured to an open. rectangular frame 12 by toggles or other suitable means. The frame is adapted to be moved intermittently from right to left to bring successive portions thereof into the spray zone of a vertically movable nozzle or spray gun, indicated generally at 14. The spray gun, as will hereinafter be described in detail, has an up-and-down movement whereby its spray traverses successive vertical strips of the hide.

The frame 12 is supported on conveyor hooks 16 each of which carries at its upper end a yoke 18; Journaled in opposite sides of the yoke are flanged wheels 20 which ride on the inner and outer flanges of an endless track 22, the track being secured to overhead supports 24. The track has two long parallel straight portions which are connected at their ends by curved portions 26. Each hook 16 is secured to an endless .chain 28 which engages with sprocket wheels 30, one below each curved portion 26 of the track. Upon rota tion of the sprocket wheels, the conveyor hooks 16 are caused to travel around the track. 85

The hooks are separated, as shown in Fig. 1, by the proper distance to permit hanging of a frame on them. Inasmuch as the length of the frame is too great to permit it to turn around the ends of the track, the straight portions of the track-are made sufficiently long to permit of attachment and removal of the frames when the hooks are running on the front straight portion of the track. The straight run of the track, therefore, is about three times the length of a single 7 frame.

In operation, a frame is hung on a pair of hooks near the right hand end of the track and if no other frame is traversing the spray zone, a rapid movement is imparted to the sprocket chain 28 to bring the left hand end of the hide into its proper position opposite the spray gun. When the left hand end of the hide approaches its proper position for spraying, the quick advancing movement of the frame is stopped and the devices for causing an intermittent movement thereof are thrown into operation. Thereafter, the spray gun moves continuously up and down over successive strips of the hide, a series of slight intermittent right to left movements being imparted to the frame v when the gun is stationary or substantially stationary at the upper or lower limit of its movement. At the completion of the spraying operation, the frame continues its movement along the left hand portion of the straight-away track, from which it may be removed by the attendant while a new frame is passing th ough the spray zone.

The mechanism by which these movements are effected will now be described. The spray gun 14, which is of any usual or preferred form, is mounted on a carriage comprising a horizontal rod 32 which is connected at its ends to two vertically moving trucks 34. Each truck 34 consists of a triangular frame in which is journaled three wheels 36. The wheels run on smooth vertical columns 38, two of the wheels being on one side of the column and one on the other in order that the gun may be maintained in its proper position. Two vertical, continuously-moving, no

sprocket chains and 40' are operated on opposite sides of the gun carriage. The right hand chain 40 runs over two sprockets 41 which are secured to shafts 42 and 42 journaled in bearings 43 secured to vertical standards 44. The left hand chain 40' runs over similar sprockets secured to shafts 45 and 45. The rod 32 on which the gun is mounted has pivoted to it a rectangular frame 46, the upper ends of which are secured to opposite lengths of the two chains 40. It will be seen that as the chain continuously traverses between the sprockets, the gun .carriage will be lifted until the frame 46 passes around the upper sprockets and will then be moved downwardly. At the limit of its downward movement, the frame 46 passes around the lower sprockets and then starts on its upward movement. The gun therefore undergoes a continuous up and down movement with a dwell between.

The apparatus is driven by a motor 50 which connects by a chain 52 with a Reeves variable speed transmission 54 having the usual wheels 56 connected by a belt 58. The shaft 60 on which the forward member of the Reeves transmission is mounted carries a sprocket 62 which connects by a chain 64 with a sprocket 66 on the shaft 42, operating the right hand gun carriage chain 40. The left hand chain 40' is also operated through the shaft 45 from the shaft 60 by a sprocket and chain connection 68.

The intermittent advancing movement of the frame by which successive portions of the hide are brought into the spray zone is effected by a sprocket wheel 70 on the shaft 42, which sprocket connects by a chain 71 with a wheel 72 on a shaft '74. A crank wheel '78 is continuously rotated through a train of gears 78. The crank wheel has a slot within which is adjustably secured the end of a pawl operating rod 82. The far end of the rod carries a pawl 84 which cooperates with a ratchet 86 on a shaft 88. The shaft 88 has secured at its end a beveled gear 90 meshing with another beveled gear 92 on the shaft 94 which carries the large conveyor sprocket 30. The parts are so constructed that the crank wheel 76 makes one complete revolution for each upward and each downward stroke of the gun carriage.

Although one-half of the revolution of the crank wheel '76 is in such a direction as to cause a movement of the pawl arm, it will be seen that the effective movement of the ratchet takes place over only a small part of the movement of the crank wheel. The parts are so adjusted that this movement occurs when the gun carriage is substantially at the tops and bottoms of its strokes in order that no appreciable movement of the frame will occur while the hide is being sprayed. By adjusting the position of the pawl arm in the slot 80 of the crank wheel, the amount of advance of the frame may be nicely adjusted to give any desired degree of overlap on the successive movements of the spray gun.

In order to effect a quick movement of the carriage independently of the regular intermittent advance, as when the apparatus is started up and it is desired to bring the first frame quickly into the spray zone, the shaft 88 is provided with a friction disk 100 which engages a cooperating beveled friction disk"102 on a shaft 104 at right angles to the shaft 88. The disk 102 is slidingly mounted on the shaft 104 and may be moved to engage the disk 100 by means of a clutch arm 106 operated by a handle 108. The shaft 104 is continuously rotated through a pair of beveled gears 110 one of which is driven by a sprocket chain 112 actuated by a shaft 113 on the rear member of the Reeves transmission. When the clutch disks 100 and 102 are brought into engagement, the main conveyor sprocket 30 is rapidly rotated, the ratchet 86 overrunning the pawl 84. In this manner, a frame may be quickly moved to any desired position.

The means for controlling the spray will now be described. Inasmuch as the hide is of irregular shape, it is desirable to provide means whereby the nozzle may be out off when no leather is presented to it. To this end, the trigger 114 on the gun is connected with a cord 116 which runs over a-pulley 118 below the lower limit of movement of the carriage, thence upwardly over a pulley 120 secured in suitable bearings near the top of the machine and thence downwardly to be attached to the carriage. The lower pulley 118 is journaled on an arm 122 which is pivoted on one of the standards 44, the opposite end of the arm carrying a magnet core 124 which is adapted to be attracted by a solenoid 126.

It will be seen that when the solenoid attracts the plunger, the trigger 114 will be pulled down regardless of the position of the carriage. When the solenoid is de-energized, the arm 122 will be restored to its original position by a spring of the usual form associated with the spraying mechanism. The limit of upward movement of the arm 122 is determined by a stop 128 adjustably mounted on a vertical arm 130. When the solenoid is energized and the trigger is pulled down, the gun is rendered operative to spray the material, and when the trigger is released, the gun is rendered inoperative.

The coating fluid is conducted from a pressure tank 132 to the gun by a flexible tube 133, cooperating with a compressed air tube 134. In 115 order to maintain a uniform spray pressure on the gun, regardless of the vertical position of the gun, an equalizing chamber 135 is provided on the gun carriage as will presently be described in detail.

The solenoid is energized from any convenient electrical source by a cable 136. The operation may be controlled manually, if desired, by any convenient form of switch located say on one of the uprights adjacent the guides for the spray 125 gun so that the operator may observe the spraying and control the operation of the gun accordingly. However, in order that the apparatus may require a minimum of attention, the automatic control shown in Figs. 5 to '7 is preferred.

This automatic control comprises a photo-electric ce1l,'together with means for directing light upon it when no part of the leather is opposed to the nozzle, suitable circuit arrangements being provided to control the operation of the solenoid. 35 As shown in Figs. 5 and 6, a complementary carriage 140, similar to the gun carriage, is arranged to move in unison with the latter but on the opposite side of the frame 12. To this end, the carriage is arranged to move vertically on columns 142 and is driven by a sprocket chain 144 running over wheels 146. The chain 144 is driven by a chain 148 connecting the lower shaft 41 with the shaft 150 on which the lower sprocket 146 is mounted. On one side of the carriage 140 is mounted an electric lamp 152 which is adapted to direct rays of light against an inclined mirror 154 supported on the gun carriage directly below the nozzle. The mirror 154 reflects the rays to a mirror 156 mounted on the carriage 140 which 150 mirror is so inclined as to reflect the rays vertically downwardly into the photo-electric cell 158 which is contained in a light-proof box 160 having an opening in the top of just suflicient size to permit the reflected beam to fall upon the sensitive cell. It is, of course, necessary that the entire apparatus be enclosed in order that the photo-electric cell may not be subject to the action of outside light. For the sake of simplicity, the enclosures are omitted from the drawings.

It will be seen that two beams of light cross the plane of the frame 12. The first beam is the one which passes from the lamp 152 to the mirror 154 and the second is that which passes from the mirror 154 to the mirror 156. The horizontal distance between the intersections of these two beams with the plane of the frame is approximately equal to the width of the zone covered by the spray gun. Also as shown in Fig. 5, the vertical position of intersection of these two beams with the plane of the frame practically coincides with the center line of the spray. It will be seen, therefore, that if either orthese beams is cut oif by the presence of leather to be coated, there will be no light on the photo-electric cell, but if neither beam is intercepted, the cell will be energized.

The cell operates in the usual manner undergoing a decrease in electrical resistance when light falls on it. The change of current between the dark condition and the energized condition is availed of to operate the solenoid. Since the change in current is too small to operate the solenoid directly, provision is made as shown in the diagram of Fig. 5, for amplifying it to such a value as will be efiective for controlling the operation of the solenoid. In this figure, the amplifying element is a thermionic tube 162, the filament of which is lighted from the secondary 164 of a transformer 166. The photo-electric cell 158 is connected between the filament and grid of the tube in series with a portion 166 of the transformer secondary. This part of the transformer is also employed to energize the plate circuit of the tube 162 in series with which is a relay 168 which controls a switch 170 in the cable 136 leading to the solenoid. As shown in Fig. '7, the switch 170 is normally closed. That is to say, when the photo-electric cell is dark and only a small current flows through the relay 168, the solenoid circuit 136 is energized. When light is permitted to fall on the cell by the absence of leather in front of the nozzle, the relay 168 is energized, thereby opening the switch 170 to deenergize the solenoid and consequently to cut off the spray.

A modified form of control which does not require a light-proof enclosure for the apparatus is shown in Figs. 8 and 9. In this construction, the material being sprayed intercepts a. plurality of air blasts except when no material is presented to the nozzle, at which time the blasts actuate switches for opening the solenoid circuit. As shown in Fig. 8, the plane of the leather is indicated at 10 and the spray nozzle at 14. The area of spray covered by the nozzle is represented by the rectangle enclosed in dot-and-dash lines in Fig. 9. At the four corners of this rectangle on the same side of the leather as the nozzle, are arranged a plurality of switch boxes 190, each of which includes a pair of separated switch contacts 192. A movable switch member 193 is adapted to connect the contacts to close the circuit. The circuit is normally maintained closed by a spring 194 encircling the member 193 outside of the box. The member 193 terminates in a concave plate 196 which is opposed to a blast of air directed by a nozzle 198 on the opposite side of the leather 10, one of such nozzles being provided for each of the switch boxes. Each contact 192 is connected with a wire 200, corresponding wires for all of the switches being connected in parallel as shown in Fig. 9, and attached to the cable 136.

It will be seen that so long as any material is interposed in the path of the spray, at least one of the nozzles will be ineffective to direct a blast of air against the plate 196 of its corresponding switch and so long as one or more of the switches remain closed, the solenoid circuit will be closed and the gun will continue to spray. However, when all of the switches are open, an occasion which arises by absence of all leatherfrom the eflective zone of the spray gun, the solenoid will 'be de-energized to release the trigger and cut out the spray.

The equalizing chamber 135 on the gun carriage will now be described. Since the fluid is forced upwardly to the nozzle from the pressure tank 132, a variation of pressure in the line occurs as the gun is moved up and down. Near the top of its movement, especially when the hides are of considerable vertical height, the pressure in theline will be considerably decreased. In order to maintain a constant pressure on the spray nozzle, the equalizing chamber 135 is included in the line 133. The flexible tube 133 connects with a pipe 202 having a check valve 204, the pipe connecting with the T 206, one branch of which connects with a pipe 208 leading into the chamber. The other branch of the T connects with a pipe 210 leading directly to the nozzle. The spray fluid enters the pipe 208 and fills the chamber to a level indicated in Fig. 4. This level is determined by the air pressure above the fluid in the chamber. At the bottom of the stroke of the carriage, when the pressure in the line is greatest, the chamber 135 will fill to its maximum level, compressing the air to a pressure determined by the tank pressure. As the carriage rises, the pressure in the pipe line tends to decrease, but the chamber maintains the required pressure on the nozzle. Inasmuch as the resistance of the nozzle is quite high, there is no appreciable loss of pressure through it, and since the amount of spray fluid used in one movement of the carriage is not great, the level of fluid in the chamber will not drop materially. The pressure is thereby maintained on the nozzle at a substantially constant value.

The pipe 208 extends downwardly to a position near the bottom of the chamber and a conical baflle 212 is secured to the bottom of the pipe. The purpose of this bafile is to prevent any outflow of air from the tank under the agitation to which the liquid is subjected in the movement of the carriage. The chamber is provided with petcocks 214, by which the fluid level and the pressure in the chamber may be adjusted to any desired values.

Having thus described the invention, what is claimed is:

1. A coating apparatus having, in combination, a support for the material to be treated, a continuous track having a straight run and curved ends. a carriage on the track for carrying the support, a spray nozzle, means for mounting the nozzle to permit movement thereof with respect to the support in a direction transverse to the direction of movement of the carriage along the track, means for continuously moving the nozzle back and forth, and means for intermittently advancing the carriage when the nozzle is at the limit of its movement in either direction.

2. A coating apparatus having, in combination, a frame for the material to be coated, a spray nozzle, means for continuously moving the nozzle back and forth to spray successive zones of the material, a carriage for the frame to permit movement of the frame in a direction transverse to the direction of movement of the nozzle, means for imparting a continuous rapid movement to the frame when it is without the spray zone, and means for imparting an intermittent slow movement of the frame when it is within the spray zone.

3. A coating apparatus having, in combination, a continuous track, a carriage on the track for carrying the material to be coated, means including a sprocket and a chain for advancing the carriage, a spray nozzle, means for mounting the nozzle to permit movement thereof with respect to the material to be coated in a direction transverse to the movement of the carriage, means for continuously moving the nozzle back and forth to spray a zone of the material, and means for intermittently advancing the carriage when the nozzle is at the limit of its movement in each direction.

4. A coating apparatus having, in combination, a track, a carriage on the track for carrying the material to be coated, a continuous chain parallel with the track and connected with the carriage, a sprocket engaging with the chain for advancing the carriage, a spray nozzle, means for moving the nozzle back and forth with respect to the work, and pawl and ratchet means for intermittently rotating the sprocket to advance successive portions of the material into spraying position.

5. A coating apparatus having, in combination, a continuous track, a carriage for the material to be coated, a chain for advancing the carriage, a sprocket for driving the chain, a spray nozzle, means for moving the nozzle back and forth with respect to the work, means for intermittently driving the sprocket to present successive portions of the work to the nozzle, and means for initially imparting a rapid advancing movement to the chain to bring the material into initial spraying position.

6. A coating apparatus having, in combination, a continuous track, a carriage on the track for carrying the material to be coated, a spray nozzle,

- means connected with the carriage for advancing it to present the material to the spray nozzle, a pawl and ratchet for intermittently driving said connections, and means for imparting an initial rapid movement to the carriage to cause the ratchet to overrun the pawl and to present the leading edge of the material to be sprayed.

'l. A coating apparatus having, in combination, a spray gun, a gun carriage, guides on which the carriage travels, an operating device on the carriage for controlling the spray through the nozale, and means for operating said device regardless of the position of the carriage comprising a cable attached at one end to the device and at the other end to the carriage, pulleys around which the cable passes beyond limits of movement of the carriage, a pivoted arm on which one of the pulleys is mounted, and magnetic means for actuating the arm.

8. An apparatus for coating material of irregular shape comprising a support for the material, a spray nozzle, a carriage for the nozzle, means for relatively moving the carriage and the material to spray a zone of the material, control devices on opposite sides of the material, means for rendering the control devices inactive when intercepted by the material to be coated, and for rendering them active when not intercepted by the material, and means operated by the control devices when rendered active to shut off the spray.

9. An apparatus for coating material of irregular shape comprising a spray nozzle, a carriage for the nozzle, a frame for the material to be coated, means for relatively moving the carriage and the frame to spray a zone of the material, a control device including a' photo-electric cell, means for directing a beam of light across the plane of the material to be coated, and for directing it upon the photo-electric cell when not intercepted by the material, and means controlled by energization of the photo-electric cell for cutting off the spray. V

10. A coating apparatus having, in combination, a spray nozzle, a carriage in the nozzle, vertical guides on which the carriage travels, a stationary pressure tank, a spray line leading from the tank to the nozzle, an equalizing chamber on the carriage, a branch connection from the spray line into the equalizing chamber and terminating near the bottom of the equalizing chamber, and a baffle on the end of the branch connection covering a considerable area of the equalizing chamber to prevent outflow of air from the chamber.

11. An apparatus for coating material of irregular shape comprising a spray nozzle, a carriage for the nozzle, a frame for the material to be coated, means for relatively moving the carriage and the frame to spray a zone of the material,acontroldevice including means for directing blasts of air across the plane of the material sitioned and on which the carriage travels, the

said guides being widely spaced apart to enable the operator to observe carefully the progress of the process of coating, a pair of endless traveling members adjacent to the guides, a common means for actuating the endless traveling members, and permanent connections between the carriage and the endless traveling members to move the carriage continuously back and forth upon the guides.

13. A coating apparatus comprising a spray nozzle,aspraynozzle carriage comprising an open frame, trucks connected thereto each truck consisting of a triangular frame in which are journaled three wheels, a pair of spaced guides upon which the said trucks travel, two of the wheels of each truck engaging one face of the guide and the third wheel engaging the opposite face, a pair of endless traveling members adjacent to said guides, means for driving synchronously the endless traveling members, permanent connections between the carriage and the endless traveling members to move the carriage first in one direction and then in the other direction, and a spray nozzle mounted in the open frame of the carriage.

14. An apparatus for coating material of irregular shape comprising a spray nozzle, a carriage for the nozzle, a frame for the material to be coated, means for relatively moving the carriage and the frame to spray a zone of the material, a control device including a photo-electric cell, a light source emitting light traversing the plane of material to be coated to impinge upon the photo-electric cell when not intercepted by the material, and electro-magnetic means controlled by the energization of the photo-electric cell for operating the nozzle. I

15. A coating apparatus comprising a spray nozzle, a carriage for the nozzle, means for reciprocating the carriage, and means for feeding the material transversely of the movements of the carriage to cause the nozzle to operate upon successive zones of material, said feeding means including a variable throw crank for varying the overlap of said zones.

16. A coating apparatus for coating sheet ma terial comprising a spray nozzle, a carriage for the nozzle, and means for imparting relative movements to the nozzle and to the sheet material in directions transverse to one another to cause the nozzle to operate upon successive zones of material, said means having provision for varying the relative extent of movement in such directions in a given period of time to vary the degree of overlap of the spray zones.

17. A coating apparatus having, in combination, a spray nozzle, a carriage for the nozzle, feeding means including an over-running clutch for normally feeding the work past the spray nozzle, and friction drive mechanism for imparting an increased speed of movement to the work.

18. A coating apparatus having, in combination, a. carriage, a nozzle mounted on the carriage, mechanism for reciprocating the carriage, and means for controlling the operation of the nozzle, said means comprising a controlling cable connected to the nozzle, and guides for the cable, one of said guides being movable to actuate the cable to control the operation of the nozzle.

19. A coating apparatus having,- in combination, a carriage, a nozzle mounted on the carriage, mechanism for reciprocating the carriage, means for controlling the operation of the nozzle, and means comprising a controlling cable arranged in a closed loop with one end connected to the nozzle and the other end fixed with relation to the carriage and movable therewith, and controlling devices for the-cable.

20. A coating apparatus having, in combination, a carriage, a nozzle mounted on the carriage, mechanism for reciprocating the carriage, means for controlling the operation of the nozzle, and means comprising a controlling cable arranged in a closed loop, one end of the cable being connected to the nozzle and the other end' being fixed with relation to the carriage and movable therewith, and guides for the cable, one of the guides being movable to actuate the controlling cable.

21. A coating apparatus having, in combination, a support for the material, a spray nozzle, a carriage for the nozzle, means for relatively moving the carriage and the material, and spaced cooperating devices responsive to presence and absence of material in position between said devices for controlling the operation of the spray nozzles.

22. A coating apparatus having, in combination, a support for the material, a spray nozzle, a carriage for the nozzle, means for relatively moving the carriage and the material, and lightresponsive controlling devices for controlling the operation of the nozzle in accordance with the presence or absence of material in position to be sprayed.

23. A coating apparatus having, in combination, a support for the material, a spray nozzle, a carriage for thenozzle, means for relatively moving the carriage and the material, and controlling devices including air blast directing means for controlling the operation of the nozzle in accordance with the presence or absence of material in position to be sprayed.

24. A coating apparatus having, in combination, a support for the material, a spray nozzle, a carriage for the nozzle, means for relatively moving the carriage and the material, and controlling devices for the nozzle including means for directing a pair of rays of light across the plane of 115 the material spaced apart approximately the width of the zone covered by the spray nozzle, said devices rendering the nozzle operative if either light ray be intercepted by the material and rendering the nozzle inoperative if neither'12O ray is intercepted.

25. A coating apparatus having, in combination, a support for the material, a spray nozzle, a carriage for the nozzle, means for relatively moving the carriage and the material, and light controlled devices for the nozzle, said devices including a photo-electric cell, thermionic tube, and transformer.

ROGER L. GRIFFIN. 

